Finding the Fourth Proportional to 2,080.40, 3,119.76 and 781.16

Step by Step Solution

1. Step 1: Write the proportion equation
   2,080.40 : 3,119.76 = 781.16 : x
2. Step 2: Convert to fraction form
   2,080.40/3,119.76 = 781.16/x
3. Step 3: Cross multiply
   2,080.40x = 3,119.76 × 781.16
4. Step 4: Simplify right side
   2,080.40x = 2,437,031.72
5. Step 5: Solve for x
   x = 2,437,031.72/2,080.40
6. Step 6: Final answer
   x = 1,171.42